Definition of terrapin in English:

noun

The northern diamondback terrapin, red fox, snapping turtle, raccoon, rabbit, skunk, opossum and blue crab, all animals that do well living close to people, have adapted nicely to the rapid changes of the Meadowlands.

‘The diamondback terrapin became one of the most economically important reptiles in the world,’ said Lovich.

Crabs or fish or even a diamondback terrapin enters a trap to feed on the bait, can't get out, dies and becomes the bait that attracts more victims.